MAC é uma linha de produtos - PC é um termo técnico. Mesmo por que alguém diria que o produto das marcas Foo é melhor que o objeto Bar
Para acomodar o nit picking (Termos em ciência da computação que usam a abreviação mac)
.mac, a file extension for macros in Agilent ChemStation
.Mac, a former name of MobileMe
MAC address, Media Access Control address or Ethernet Hardware Address (EHA)
Mac OS, an operating system of Apple's Macintosh
MAC times, file system metadata which record when an object was last "modified" (contents), "accessed" (read), and "changed" (permissions) (the last one varies between operating systems; for instance, Unix/Linux tracks "change", while Windows tracks "creation" instead)
Macintosh, a brand of personal computers and computer operating systems made by Apple Inc.
Mandatory access control, a type of access control in computer security
Media Access Control, sublayer of Data Link layer
Message authentication code, used to authenticate a message in cryptography
Migration Authorisation Code, a unique code used when switching between DSL Internet service providers in the UK
Mission Assurance Category, a designation used in the United States Department of Defense, reflecting the importance of an information system for the successful completion of a DoD mission, especially in regard to availability and integrity
Multiplexed Analogue Components
Multiply–accumulate or Multiplier–accumulator
Fonte - Wikipedia